UBS Axcera 420A Low Power Television User Manual

UBS-Axcera Low Power Television Table of contents

a href="https://usermanual.wiki/UBS-Axcera" itemprop="url"> UBS Axcera >

Chapter 4

100 Watt High Band VHF Transmitter                 Chapter 4, Detailed Alignment Procedures420A, Rev. 0 4-1Chapter 4Detailed Alignment ProceduresIf this transmitter contains the (optional)4.5 MHz composite input kit, thebaseband video input is used when thebaseband video is connected to J2 and abaseband select is connected to J18 pins6 and 7 on the rear of the tray.Check that the RF output at J15 of thetransmitter is terminated into a dummyload of at least 100 watts. Whileperforming the alignment, refer to theTest Data Sheet for the transmitter andcompare the final readings from thefactory with the meter readings on thetray. They should be very similar. If areading is more than 10% different, aproblem with the tray may exist. Switchon the on/off AC circuit breaker on therear of the tray.4.1 Alignment of the 420ATransmitter4.1.1 Baseband SectionThis tray has adjustments for video andaudio modulation levels and other relatedparameters.Connect an NTSC composite video testsignal input (1 Vpk-pk) or an (optional)4.5 MHz composite input to thetransmitter video input jack J2 on therear of the tray.Note: J2 is a loop-through connectedto J1. It can be used as a basebandvideo source if the jumper W1 on J3of the sync tip clamp/modulatorboard is removed.Connect the baseband audio, if it isbalanced audio (+10 dBm), to theterminal block (TB1) or connect thecomposite audio (stereo) (1 Vpk-pk) tothe BNC jack (J13).Note: J13 is a loop-throughconnected to J3. It can be used as acomposite audio source if the jumperW4 on J12 of the aural IFsynthesizer board is removed.The baseband audio is not used with the(optional) 4.5 MHz composite input.Observe the front panel meter on thetray. In the video position, the meterindicates active video from ≅ 0.3V to1.0V. With an input video of 1 Vpk-pk,the display should indicate 100 IRE unitsat white. If the reading is at not theproper level, the overall video level canbe changed by adjusting the video levelcontrol (R15) on (A5) the sync tipclamp/modulator board (1265-1302).Switch the meter to the audio positionthat will indicate the audio deviation(modulation level) of the signal; themeter indicates from 0 to 100 kHz. Theaural IF synthesizer board was factoryset for ±25 kHz deviation with a balancedaudio input of +10 dBm. If the reading isnot the correct level, adjust the balancedaudio gain pot R13 on the aural IFsynthesizer board, as needed, to attainthe ±25 kHz deviation. The aural IFsynthesizer board was factory set for±75 kHz deviation with a compositeaudio input of 1 Vpk-pk. If the reading isnot correct, adjust the composite audiogain pot R17 on the aural IF synthesizerboard, as needed, for the ±75 kHzdeviation.
Download:
Mirror Download [FCC.gov]
Document ID80251
Application ID4c+HKm7jMl4rg9yoqQg3Tw==
Document DescriptionChapter 4
Short Term ConfidentialNo
Permanent ConfidentialNo
SupercedeNo
Document TypeUser Manual
Display FormatMicrosoft Word - pdf
Filesize7.58kB (94721 bits)
Date Submitted2000-01-10 00:00:00
Date Available2000-04-03 00:00:00
Creation Date2001-05-03 07:53:22
Producing SoftwareAcrobat Distiller 4.0 for Windows
Document Lastmod2001-05-03 07:53:24
Document TitleChapter 4
FCC ID Filing: OUS420A

Navigation menu